The invention relates to a method and a device for regulation or control of a restraint system in a vehicle having a safety belt and an operation or convenience function. The belt retraction force acting on the safety belt is set in a situation-related fashion. That is, the operation and convenience functions adapt to a situation by increasing or decreasing the force.
Seat belt systems with belt pretensioners that use a motor to tension a restoring spring as a function of parameter for returning the safety belt are generally known. Such systems with belt pretensioners are disclosed, for example, in DE 102 04 475 A1, DE 102 04 476 A1, DE 102 04 477 A1 and DE 101 58 871 A1.
Further methods are known for the continuous adaptation of the belt retraction force. DE 103 10 069 A1 discloses determining measured values for the tensile forces acting on the belt band, e.g., force measuring signals during normal driving operation, during a pre-crash phase or during an accident, and using them for regulation or control of the restraint system.
DE 196 36 448 C2 discloses determining the position of the driver's own vehicle relative to an object detected in the vicinity of the vehicle, and controlling a belt tension control mechanism as a function of the proximity of the object relative to the driver's own vehicle. In this case, the belt tension control mechanism is used to hold the safety belt in a predetermined number of modes with different prescribed belt tension values.
One object of the invention is to specify a method and a device for control or regulation of a restraint system in a vehicle that, in addition to security, enables operational convenience for the restraint system.
This and other objects are achieved in a restraint system for a passenger of a vehicle in that at least one operation, safety or convenience function is set on the restraint system by adapting in a situation-related fashion a belt retraction force acting on the safety belt. The belt retraction force or belt restraint force is understood, in particular, as the tensile force acting on the safety belt when the safety belt is donned (put on) or taken off. In this case, increasing the belt retraction force increases the tension of the safety belt; while a reduction in the belt retraction force effects a loosening of the belt. An operation function of the restraint system is understood, in particular, as the support of the occupant when donning and taking off the safety belt, for example through a loosening or tensioning of the safety belt. A safety function of the restraint system is understood, in particular, as the restraining of an occupant that is required in a critical situation and is supplied by the safety belt, and thus a strong tensioning of the safety belt. A convenience function is understood, in particular, as the setting of an individual wearing level on the safety belt.
The advantage of the invention consists in that an improved convenience function, safety function or operation function of the safety belt is enabled by setting the safety belt particularly in a fashion that is continuous and adapted to the respective vehicle situation or surrounding situation. To this end, both the instantaneous operating situation of the driver's own vehicle, and the surroundings of the vehicle are determined such that upon determination of the situation an appropriate belt retraction force is set, for example, upon fastening or unfastening the belt. The vehicle occupant is restrained in a way adapted to the instantaneous situation, or the vehicle occupant is supported when donning or taking off the safety belt. This leads to a substantial improvement in and enhancement of convenience in belt wearing, belt safety and belt operation.
To improve convenience in belt operation, the belt retraction force is reduced to a prescribed belt donning value upon unlocking the vehicle or upon actuating a central locking system of the vehicle. By reducing the belt retraction force as early as when unlocking the vehicle, the vehicle occupant is supported when subsequently donning the safety belt by virtue of the fact that the safety belt can be more easily manipulated and donned because of the lowering of the force to a defined level of operational convenience. The belt retraction force is reduced, in particular, when the vehicle is stationary. Again, a check is made in advance as to whether the respective safety belt has not already been donned.
The opening of a vehicle door is identified as a further situation, and used to set the belt retraction force to a prescribed belt donning value. In particular, the belt retraction force is lowered to a level of operational convenience that supports the occupant when donning the belt.
Moreover, the belt retraction force can be reduced to a prescribed belt donning value upon detection of an occupant in a seat so as to facilitate fastening. It is possible, therefore, to set the belt retraction force on the relevant safety belt in a way that is related to seating place and individual.
The belt retraction force is continuously or uniformly and slowly raised to a prescribed belt donning value after termination of the fastening operation for the purpose of pleasant convenience in wearing the belt while driving. The locking of the belt lock, for example, is monitored to this end. Thus, the belt slack can be present before or can be removed as driving begins, such that the occupant is held sufficiently by the safety belt.
In a further embodiment, it is possible to slowly raise the belt retraction force after termination of the fastening operation and expiry of a prescribed time or upon the reaching of a prescribed speed of the driver's own vehicle. This also minimizes the belt slack by raising the belt retraction force to a prescribed belt wearing level or to a prescribed force level. Alternatively, after the extension of the safety belt to a prescribed maximum extension value and a following reduction in the belt extension to a prescribed belt donning value, the belt retraction force can be raised slowly and continuously in order to minimize the belt slack.
A slow continuous and markedly short rise in the belt retraction force results after termination of the fastening operation and expiry of a prescribed time or upon the reaching of a prescribed vehicle speed, in order to effect the belt slack minimization quickly, for example given the presence of a high speed of the driver's own vehicle. Again, the belt retraction force can be substantially raised given a seat occupancy detection identified outside the optimum position.
Furthermore, upon the vehicle engine being turned off, upon withdrawal of the ignition key or upon actuation of the belt lock in order to unfasten the safety belt, the belt retraction force is substantially raised to a prescribed value or a force level for assisting the taking off of the safety belt. This enables a reliable retraction of the safety belt.
In the event of the presence of a further situation, such as after the safety belt has been taken off, after the reaching of a prescribed minimum belt length, after the locking of the vehicle, after an opening and closing of the vehicle door, or after expiry of a prescribed time, the belt retraction force is set from the wearing level to a prescribed operating level. That is to say, the safety belt is appropriately loosened for good operational convenience such that the extension force is reduced upon the next fastening, and the occupant is assisted when pulling the safety belt.
In order to avoid the flapping of a safety belt that is not required during driving, for example, in the event of uneven roads, the belt retraction force is set to a prescribed belt donning value, in particular to a higher value relative to the operating level, for an unoccupied seat and for when the driver's own vehicle exhibits a certain speed.
Again, during driving with an open folding roof or as a function of the vehicle speed, the belt retraction force is set for an unoccupied seat to a prescribed belt donning value and raised relative to the normal operating level such that the belt is tensioned and a flapping of the belt is prevented or at least reduced. It is also possible in this case to set the belt retraction force as a function of speed.
In a further embodiment, given identification of a sport driving mode or of a winding drive, the belt retraction force is set in a fashion related to seat position, in particular being set differently and individually for the driver and the remaining occupants. The different perceptions by the driver and by another occupant are taken into account in this case, and the safety belt is appropriately tensioned in a weak or strong fashion.
In order to improve the belt wearing comfort in critical situations, the belt retraction force or the belt holding force is appropriately set or adapted before or during lateral accelerations and the safety belt is appropriately tensioned in relation to the situation.
The situation related settings of the belt retraction force, such as the steering angle, the lateral acceleration, the yawing rate, the vehicle speed or the road profile are determined with the aid of sensors or of a navigation system, for example with the aid of digital roadmaps, in order to determine the situation. The measured values are fed to an evaluation unit for determining the operation or surrounding situation with the aid of one of the operation, safety or convenience functions is set on the restraint or belt comfort system by virtue of the fact that the belt retraction force acting on the safety belt can be set via a setting device as a function of the situation determined. By way of example, the setting device for the belt tensioning mechanism is provided by a conventional spring setting device for continuously setting a spring force on a restoring spring of the safety belt, or an electric motor, connected to a winder shaft, for setting the belt tension on the safety belt.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying diagrams.
Mutually corresponding parts are provided in both figures with the same reference symbols.